Various stage vacuum pumps, and alternatively expanders, generally relate to devices that alter or reduce the pressure of gases within a container, typically to very low vacuums, or alternatively produce power as a gas expands. More specifically, these devices refer to multiple stages of scrolls that greatly increase the vacuums or pressures obtained during usage.
Scroll devices have been used as compressors, expanders and vacuum pumps for many years. In general, they have been limited to a single stage of compression due to the complexity of two or more stages, formed for compression, and for operation. In a single stage, a spiral involute or scroll upon a rotating plate orbits within a fix spiral or scroll upon a stationary plate. A motor shaft turns a shaft that orbits a scroll eccentrically within a fixed scroll and the eccentric orbit forces a gas through and out of the fixed scroll, thus creating a vacuum in a container in communication with the outlet from the fixed scroll. An expander operates under the same principle, only turning the scrolls in reverse, during their operations. When referring to compressors, it is understood that a vacuum pump can be substituted for a compressor, and that the expander can be an alternate usage when the scrolls operate in reverse from an expanding gas.
Often oil is used during manufacture and operations of compressors. Oil free or oil less scroll type compressors and vacuum pumps have difficult and expensive manufacturing, due to the high precision of the scroll in each pump and compressor. For oil lubricated equipment, swing links often minimize the leakage from gaps in the scrolls by allowing the scrolls to contact the plate of the scroll. Such links can not be used in an oil free piece of equipment because of the friction and wear upon the scrolls. If the fixed and orbiting scrolls and oil free equipment lack precision, leakage will occur and the equipment performance will decline as vacuums take longer to induce or do not arise at all.
Prior art designs have previously improved vacuum pumps, particularly in the design of the tips of the scrolls. In the preceding work of this inventor, U.S. Pat. No. 6,511,308, a sealant is applied to the two stage scrolls during manufacturing. The pump with the sealant upon the scrolls is then operated which distributes the sealant between the scrolls. The pump is then disassembled and lets the sealant cure. After curing the sealant, the pump is reassembled for use. During use, this patented pump only achieves a vacuum on the order of 100 mt.
In addition, the current inventor has a variety of patents that relate to two stage scroll devices. For example, Mr. Shaffer's U.S. Pat. No. 6,439,864, is upon a Two Stage Scroll Vacuum Pump With Improved Pressure Ratio and Performance. The various stages of this pump and spiral involute wraps are of differing sizes in the different stages of the pump construction. This has an effect upon the compression ratio in the operations of the pump, in order to increase its efficiency.
Another patent to Shaffer, U.S. Pat. No. 7,942,655, discloses an advance scroll compressor, vacuum pump, and expander. This device uses bellows that spans between the fixed and orbiting scrolls and hermetically seals the scroll device during its functioning. The bellows also accommodates liquid cooling of the compressor during its operations.
A further patent to Mr. Shaffer, U.S. Pat. No. 8,523,544, shows another three stage scroll vacuum pump. This pump has three stages of fixed scrolls and orbiting scrolls that operate simultaneously. The structure of the scrolls, or the housing for the pump, incorporates fins that have the effect of a heat sink for disseminating the generated heat of the vacuum pump, during its operations.
A further published application of the inventor, U.S. 2011/0176948, discloses a semi-hermetic scroll compressor, vacuum pump, and expander. This invention also incorporated heat sinks upon its structure in order to increase the heat transfer from the compressor during its functioning.
A further published application of the inventor herein is upon a three stage scroll vacuum pump, published under No. U.S. 2011/0256007. This device incorporates magnetic couplings in order to attain the functioning of its orbiting scroll, so that atmosphere does not infiltrate the pump during its usage.
A unique aspect of the present disclosure is the use of a multi-stage scroll vacuum pump and/or compressor, that may be used to attain and is capable of achieving very high vacuums, (low absolute pressures), or high pressures for a multi-stage compressor that are very desirable for a number of applications.
Other U.S. patents have shown related technology, and U.S. Pat. No. 3,802,809, which issued to Vulliez, disclosed a pump having a scroll orbiting within its fixed scroll. Beneath the fixed disc, a bellows guides the gases evacuated from a container. The bellows spans between the involute and the housing, nearly the height of the pump. The pump and many other parts are cooled by ambient air in the vicinity of the pump.
The patent to Mulhouse, et al, U.S. Pat. No. 3,011,694, discloses an encapsulating device for expanders, compressors or the like. Thus, it shows an early multi type of compressor, pump or expander, as noted.
A patent to McCullough, U.S. Pat. No. 3,986,799, shows a fluid-cooled, scroll-type, positive fluid displacement apparatus. It utilizes stationary and orbiting scroll members of a scroll-type apparatus.
A further patent to McCullough, and the inventor herein, early on, U.S. Pat. No. 3,994,636, shows an axial compliance means with radial sealing for scroll-type apparatus.
A further patent to McCullough, et al, U.S. Pat. No. 4,192,152, shows another scroll-type fluid displacement apparatus with peripheral drive.
The patent to Hiraga, et al, U.S. Pat. No. 4,340,339, shows a scroll-type compressor with oil passageways through its housing.
The patent to Buttersworth, U.S. Pat. No. 4,415,317, discloses a wrap element and tip seal for use in fluid apparatus of the scroll-type. The purpose for the seal is to enhance the efficiency of operations of the device for both compression and for pumping purposes.
The patent to Eber, et al, U.S. Pat. No. 4,416,597, shows a further tip seal back-up member for use in fluid apparatus of the scroll-type.
The patent to Teegarden, U.S. Pat. No. 4,462,771, shows another improvement upon a wrap element and tip seal for use in fluid apparatus of the scroll-type and the method for making same.
The patent to Leclaire, et al, U.S. Pat. No. 4,718,836, shows a reciprocating completely sealed fluid-tight vacuum pump.
The patent to Nakamura, et al, U.S. Pat. No. 4,730,375, shows a method for the assembly of a scroll-type apparatus.
The patent to Kotlarek, et al, U.S. Pat. No. 4,867,657, shows a scroll compressor with axial balanced shaft.
Another patent to McCullough, et al, U.S. Pat. No. 4,892,469, shows a compact scroll-type fluid compressor with swing-link driving means.
The scroll-type fluid apparatus having sealing member in the recess forming the suction space, to Okada, et al, is disclosed in patent U.S. Pat. No. 5,160,253.
It should be noted that most of these prior art patents relate to a single plate pair for use within compressor apparatus.
A further patent to the inventor herein, Mr. Shaffer, U.S. Pat. No. 5,466,134, is upon a scroll compressor having idler cranks and strengthening and heat dissipating ribs. This is also upon a single plate pair for forming the scroll compressor.
Another patent to the inventor herein, Mr. Shaffer, is U.S. Pat. No. 5,632,612, shows a scroll compressor incorporating a tip seal.
The patent to Shin, et al, U.S. Pat. No. 5,632,613, shows a lubricating device for horizontal type hermetic compressor.
Another patent to Shaffer, U.S. Pat. No. 5,752,816, shows a scroll fluid displacement apparatus with improved sealing means.
A further patent to the inventor herein, U.S. Pat. No. 5,759,020, shows a scroll compressor having the tip seals and idler crank assemblies.
The patent to Liepert, U.S. Pat. No. 5,855,473, shows a displacement rate, scroll-type fluid handling apparatus.
The patent to Pottier, et al, U.S. Pat. No. 5,951,268, shows a spherical vacuum pump having a metal bellows for limiting circular translation movement.
A further patent showing various scrolls is disclosed in the patent to Claudet, U.S. Pat. No. 5,987,894, disclosing a temperature lowering apparatus using cryogenic expansion with the aid of spirals.
Another patent to the inventor herein, U.S. Pat. No. 6,050,792, shows a multi-stage scroll compressor.
Another patent to the inventor herein, Mr. Shaffer, U.S. Pat. No. 6,129,530, discloses a scroll compressor with a two piece idler shaft and two piece scroll plates. This is just a plate pair forming a scroll compressor.
The patent to Fujioka, et al, U.S. Pat. No. 6,190,145, shows a further scroll fluid machine.
A patent to Lizuka, U.S. Pat. No. 6,379,134, discloses a scroll compressor having paired fixed and movable scrolls. This is a multi-scroll compressor that incorporates a pair of fixed scrolls, and orbiting scrolls.
A published application to Ni, U.S. 2007/0172373, shows a scroll-type fluid displacement apparatus with fully compliant floating scrolls.
The published application to Stehouwer, et al, No. U.S. 2009/0246055, shows a discharge chamber for dual drive scroll compressor.
These are examples of the prior art known to the applicant herein.
In some applications scroll-type vacuum pumps have notoriety for achieving high vacuums. A few large scroll vacuums pumps can achieve vacuums as high as 50 mt. However industry, science, and research still demands compact vacuum pumps, including compressors, that can yet achieve higher vacuums and high pressure gas.
The present invention overcomes the limitations of the prior art where the need exist for higher vacuums in equipment of compact form. That is, the art of the present disclosure, a multi-stage scroll vacuum pump, utilizes structure that allows for the generation of very high vacuums, when formed as a pump, or when constructed as a compressor, can attain very high pressures, from smaller equipment, for use for operating more compact machinery and equipment, even in hand held devices, in both industrial and cooling and heating equipment, amongst other applications.